Improving quantification of intravascular fluorescence imaging using structural information

source:© 2012 Physics in Medicine & Biology

Intravascular near-infrared fluorescence (iNIRF) imaging can enable the in vivo visualization of biomarkers of vascular pathology, including high-risk plaques. The technique resolves the bio-distribution of systemically administered fluorescent probes with molecular specificity in the vessel wall. However, the geometrical variations that may occur in the distance between fibre-tip and vessel wall can lead to signal intensity variations and challenge quantification. Herein we examined whether the use of anatomical information of the cross-section vessel morphology, obtained from co-registered intravascular ultrasound (IVUS), can lead to quantification improvements when fibre-tip and vessel wall distance variations are present. The algorithm developed employs a photon propagation model derived from phantom experiments that is used to calculate the relative attenuation of fluorescence signals as they are collected over 360° along the vessel wall, and utilizes it to restore accurate fluorescence readings. The findings herein point to quantification improvements when employing hybrid iNIRF, with possible implications to the clinical detection of high-risk plaques or blood vessel theranostics.
[Read More…]

Fig. 3 Experiment for validation of the algorithm: (a) phantom schematic: two straws containing the same concentration of fluorescent dye at different distances from the catheter; (b) iNIRF longitudinal image of the straws A and B and cross-section formation of a particular pullback position of interest; (c) corresponding IVUS cross-section of the straws and their corresponding edges; (d) iNIRF cross-section overlaid on the segmented IVUS cross-section is used for the correction of the iNIRF signal; (e) correction of the iNIRF image along the entire pullback.

G.Mallas, D. H. Brooks, A. Rosenthal, R.N.Nudelman, A. Mauskapf, F.A.Jaffer and V. Ntziachristos, “Improving quantification of intravascular fluorescence imaging using structural information,” Phys. Med. Biol. Vol. 57, pp. 6395–6406 (2012).